Blender sverchok lofting with array of boxes
I would approach this differently, 


First create the curved surface by lofting, 
Use modulo to make a masklist to discard the faces that represent the space in-between the planks
Then finally extrude the faces using the Solidify node (via the Normal to turn the faces into "plank" geometry.


use the SV Import / Export panel to import this gist:
https://gist.github.com/2bda764a9f6aa7e9a6aca69d7181bdaa



here the usage of Solidy Node and Delete Loose (the "rest" verts that aren't used)



as a gist: https://gist.github.com/0216592fedb22856d4f3778e4187cec0